The present invention relates to a staple gun that includes an electro-magnetic valve which activates a shaft to seal an opening communicating with the main passage so as to change the path of the pressurized air to eject the staple.
A conventional staple gun is shown in FIG. 1 and generally includes a handle 1xe2x80x2 with a main passage 11xe2x80x2 which is connected to a source of air from a compressor (not shown) and a barrel is connected to the handle 1xe2x80x2 with a chamber 10xe2x80x2 defied in the barrel. A cylinder 24 is received in the barrel 10xe2x80x2 and an end mount assembly 2xe2x80x2 is connected to a rear end of the barrel and a nose is connected to a font end of the barrel. An end cap 22 is movably connected to an inside of the end mount assembly 2xe2x80x2 and biased by a spring 22 so as to seal an open end of the cylinder 24 in which a piston 25 is movably received in the cylinder 24. A magazine for receiving staples is connected to the nose. A recess 12xe2x80x2 is defined in a wall of the handle 1xe2x80x2 and a trigger valve 4 is received in the recess and can be activated by a trigger 5xe2x80x2. Pressurized air may enter the recess 12xe2x80x2 via a gap between the valve 4 and the opening in the wall of the handle 1xe2x80x2 and enters a tube 3xe2x80x2 engaged with a hole 14 defined in an inside of the handle 1 and a path 20xe2x80x2. The pressurized air enters a space between the end cap 22 and the end mount assembly 2xe2x80x2 via the path 20xe2x80x2 so that the opening of the cylinder 24 is sealed by the end cap 22 by the pressure in the space and the spring 21.
Referring to FIGS. 2 and 3, when a safety plate 55 is pushed toward the trigger 5xe2x80x2 and the trigger 5xe2x80x2 is squeezed, the shaft of the trigger valve 4 is shifted to seal the opening communicating with the recess 12xe2x80x2, and the pressure in the space mentioned above is reduced so that the end cap 22 is pushed toward the end mount assembly 2xe2x80x2 by the pressure in the main passage 11xe2x80x2. Once the end cap 22 is moved to open the open end of the cylinder 24, the piston 25 is moved to eject a staple by a plate connected to the piston 25 from the nose. Air in the cylinder 24 is pushed out via orifices defined through the wall of the cylinder 24 into the chamber 10xe2x80x2. Referring to FIG. 4, after shooting, the trigger 5xe2x80x2 is released and the air in the chamber 10xe2x80x2 enters the cylinder 24 again to push the piston 25 back to its original position. Simultaneously, air in the main passage 11xe2x80x2 enters the tube 3xe2x80x2 and the path 20xe2x80x2 to assist the spring 21 to move the end cap 22 to seat the open end of the cylinder 24 again.
The safety plate 55 and the trigger 5xe2x80x2 are exposed and protrude from the barrel of the staple gun so that they could be tangled by other object or activated unintentionally.
The present invention intends to provide a staple gun wherein path of the pressurized air is changed simply by moving a shaft of an electro-magnetic valve and the shooting processes are simplified and convenient for the users especially for continuously shooting.
In accordance with one aspect of the present invention, there is provided a staple gun which comprises a barrel with a cylinder received in a chamber of the barrel and an end mount assembly is connected to a rear end of the barrel. An end cap movably seals an open end of the cylinder and a spring is biased between the end cap and an inside of the end mount assembly.
A handle is connected to the barrel and a main passage is defined in the handle so as to be connected to a compressor. The main passage communicates with the chamber in the barrel and an opening which is defined through a wall of the handle. A recess is defined in the handle for receiving an electro-magnetic valve therein and communicates with the opening. The electro-magnetic valve has a shaft which is movable to seal the opening when the electro-magnetic valve is activated. A switch is received in the handle and electrically connected to the electro-magnetic valve. A button is connected to the switch and exposed from the outside of the handle.
A tube is transversely received in the main passage. A first path is defined in the handle and communicates with the recess and a second path in the tube. A third path is defined in the end mount assembly and communicates with the second path and a space defined between the end cap and the end mount assembly.